820539720 has 960 divisors, whose sum is σ = 3893218560. Its totient is φ = 150543360.

The previous prime is 820539703. The next prime is 820539721. The reversal of 820539720 is 27935028.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820539721) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 35675629 + ... + 35675651.

It is an arithmetic number, because the mean of its divisors is an integer number (4055436).

Almost surely, 2^820539720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820539720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1946609280).

820539720 is an abundant number, since it is smaller than the sum of its proper divisors (3072678840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820539720 is a wasteful number, since it uses less digits than its factorization.

820539720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 820539720 is about 28645.0644963491. The cubic root of 820539720 is about 936.1954719958.

The spelling of 820539720 in words is "eight hundred twenty million, five hundred thirty-nine thousand, seven hundred twenty".